However, in writing that post, I may have made a mistake. It’s not easy for a stubborn little edublogger to admit he should change his mind, but a new development this week might just do it. I wrote the following sentence: “It’s extraordinarily challenging to make broad, facile comparisons between the two sectors of education.”

It may not be terribly challenging at all to make simplistic comparisons. What’s more, it appears eminently possible to make meaningful comparisons between public and private schools on a number of academic data points. Yesterday, the local nonprofit group ACE Scholarships released a pilot analysis showing how scholarship students in 6 of their 150 partner schools fare compared with charter and other public school options available.

To my policy wonk friends, perhaps the most interesting piece of this work is the ability to compare student proficiency on different tests — whether it’s the TCAP used in public schools or a variety of norm-referenced tests, such as the Iowa Test of Basic Skills (ITBS) or TerraNova (designed by the same people who made TCAP). Overall, the private schools come out significantly ahead, and to a slightly lesser extent the ACE Scholarship students in those schools.

In fairness, I have to say it would be helpful for other researchers to scrutinize the methods. And it was announced that the next phase of research will include a much broader study (sounds like a lot of data collection!) to test the conclusions and see if they hold up. Yet it might be hard to close the incredible gap observed in four-year graduation rates: below 70% for comparable public schools and 92.67% for ACE private schools (while serving a higher share of low-income students).

One data point prominently reported is the ACT test results all Colorado 11th-grade students have to take. As the researcher and author Didi Fahey explains, that is not only a comparison of “apples to apples” but of “Fuji apples to Fuji apples.” On that score, ACE scholarship kids do a little better on English and reading, and outperform significantly in science, though not so much in math.

But there’s a lot more to the research than just academic scores. Among the other positive comparisons made between the set of private schools and the set of public schools is attendance rate, re-enrollment, student use of time, and parent involvement. All of which comes down in favor of the importance of school choice. The harder question to figure is the “why” explanation, but maybe someone can take a look there, too.

This interesting study certainly isn’t the be-all and end-all on important questions regarding school choice and scholarship tax credits. But as far as I can tell, it’s a breakthrough for a group like ACE Scholarships to make this sort of investment in thoughtful and rigorous research, to begin to lay it out on the line.

On the question of how well public and private school performance can be accurately and effectively compared, my little mind is starting to turn. And now my youthful curiosity and impatience start to kick in: Now I can’t wait to find out what a closer look and the bigger study will show.